OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

How do sperm cells enhance their swimming ability?

1. By having a rigid structure to push forward

2. By having a strong tail for movement

3. By their spherical shape to glide smoothly

4. By being lighter than other cells

The correct answer is: By having a strong tail for movement

Sperm cells enhance their swimming ability primarily due to the presence of a strong tail, also known as a flagellum. This tail exhibits whip-like movements that propel the sperm cell forward through the fluid environment of the reproductive tract. The tail is specialized for motility and is a critical adaptation that allows sperm to navigate towards the egg for fertilization. Its structure, which is made up of microtubules and surrounded by a plasma membrane, enables it to generate the necessary force for effective swimming. The other choices provide characteristics that do not significantly contribute to the swimming effectiveness of sperm cells. For instance, a rigid structure might limit flexibility and maneuverability, which are essential for navigating through various environments. While a spherical shape can be beneficial for some cells, it does not promote movement as effectively as the whip-like motion of the tail. Lastly, the concept of being lighter than other cells does not directly influence the swimming capacity but rather could affect how easily the sperm cell can move through a given medium. Therefore, the strong tail is essential for the locomotion of sperm cells, making it the correct choice.